title: A study of air pollutants and acute asthma exacerbations in urban areas: status report.
mesh_terms: D000208:Acute Disease; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity*; D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D002947:Cities; D006801:Humans; D009589:Nitrogen Oxides / Q000032:analysis / Q000633:toxicity; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D010126:Ozone